I think all "like items" that are currently have an C-M and E-M version should have the E-M version simply expanded to a C-M item.
For example all of the resistance models (original four modules prior to the new hybrids). There should only be one version of each model that ranges from Common to Mythical. other examples would include grappling hooks, teleports, blue madness, red wraith, supreme cannon, rapid destruction, storage units, etc..
This would most certainly expand the relevant inventory for most people while still maintaining "non like" L-M items such as scopes, torsos, claw and the new hybrid modules. It could also recued the effect of less that desired L-M drops (for example if you have 7 deliriums and no L-M resistance modules).